Adds python 3.9 to build matrix.

.travis.yml

@@ -5,7 +5,7 @@ matrix:
     # Full tests (with online API)
     - os: linux
       language: python
-      python: 3.7
+      python: 3.9
       dist: xenial
       sudo: true
       env:
@@ -40,6 +40,13 @@ matrix:
       sudo: true
       env:
         - TO_TEST=TEST_MOCK
+    - os: linux
+      language: python
+      dist: xenial
+      python: 3.9
+      sudo: true
+      env:
+        - TO_TEST=TEST_MOCK
 
 
     # Install tests
@@ -53,7 +60,7 @@ matrix:
       language: python
       dist: xenial
       sudo: true
-      python: 3.8
+      python: 3.9
       env:
         - TO_TEST=INSTALL
       if: type = cron